I'm not getting it.
You lock the car but the trunk (boot) does not lock at the same time?
You should check the wire harness where the trunk lid wires connect to the fender. As the trunk opens and closes, these wires are flexed. The eventually break. If the right wire is broken, the trunk won't lock on command from the control module.
The trunk lock has a manual position where it locks because of the key position, not because of the status of the doors. Insert the key and turn it to the right then take the key out. The trunk (boot) will be locked all of the time, and you must use the key again to open it. It's a bit of a pain, but it is a work-around that you can use.
PS
I'm in the States, where we do not have the Compact, but the rear of the car should open the same way as the other cars, so even if I describe the location wrong, the idea should be valid and you just have to work with the variance. Sorry for that.
You lock the car but the trunk (boot) does not lock at the same time?
You should check the wire harness where the trunk lid wires connect to the fender. As the trunk opens and closes, these wires are flexed. The eventually break. If the right wire is broken, the trunk won't lock on command from the control module.
The trunk lock has a manual position where it locks because of the key position, not because of the status of the doors. Insert the key and turn it to the right then take the key out. The trunk (boot) will be locked all of the time, and you must use the key again to open it. It's a bit of a pain, but it is a work-around that you can use.
PS
I'm in the States, where we do not have the Compact, but the rear of the car should open the same way as the other cars, so even if I describe the location wrong, the idea should be valid and you just have to work with the variance. Sorry for that.